Propeller



Sept. 10, 1935. J. WEcHwALD PROPELLER INVENT'OR r .J'oHN WEICW::.

Patented Sept. 10, 1935 UNITED STATES mitin OFFICE 15 Claims.

This invention relates to propellers and has among its objects to provide a new and useful propeller for aircraft which is characterized by a comparatively high propulsive eificiency and which propeller may be adapted for use With watercraft, blowers, suction fans, and other apparatus and devices.

The prcpeller as shown diagrammatically in the illustrations eomprises a pair of propeller blades of novel design or configuraticn, and it is obvious, that the propeller may be made with two or more blades to suit the purpose to which it may be applied, said blades being preferably formed integrally with the hub portion as shown in the attached drawings.

Another object of my invention is found in the provision of a propeller having blades so constructed that their pitch increases or evolves from zero at substantially the center of the hub toward the ends or tips of the blades, said blades also being enlarged or formed with a pair of oppositely disposed integral lobes-or extensions, one of such lobes or extensions being on the leading edge of the blade and the other on the trailing edge of the blade.

A further object of the invention resides in the arrangement of such lobes or extensions or enlarged areas of the bladetip whereby such extended areas are relatively offset or disposed at relatively different radii from the center of the propeller drive shaft and in such manner that preferably the extension or lobe on the leading edge of the blade is formed on a shorter radius from the center of revolution of the propeller while the other lobe or extension which is formed on the trailing edge of the blade is disposed on a longer radius from the center of revolution of the propeller.

A still further object of my invention is found 40 in so fabricating each blade that the width thereof is substantially uniform from the hub portion to the tip thereof, exclusive of the extensions or lobes, which obviously increase the width of the blade at such portions.

With the above and other objects in View, my invention consists in the novel Construction and arrangement of the propeller parts and elements shown in preferred embodiment in the attached illustrations, described in the following specifica- 50 tions, and particularly pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a side elevation of an aircraft propeller embodying my invention.

Fig. 2 is an edge View of the propeller.

Figs. 3 and 4 are respectively cross-sections taken on lines respectively 3-3 and 4-4 of Fig. 1.

Fig. 5 is a top View of the blade.

Fig. 6 is a side elevation of a watercraft propeller einbodying my invention.

Fig. '7 is an edge View of same.

Figs. 8 and 9 are respectively cross sections taken on lines 8-8 and iii of Fig. 6.

Fig. 10 is a top View of the blade.

It will be noted from the drawings, that the 10 propeller i& consists of a pair of oppositely disposed blades !Q and m and that each blade is iormed with a pair of oppositely disposed lobes or enlarged areas near the tip thereof forming integral extensions of the blade. The lobes 15 or extensions E! as here shown on the leading edges of the blades are ormed on a shorter radius from the center of the revolution of the propeller than the lobes or extensions i2 on the trailing edge. From the simple experiments that 20 I have been able to make at this time, it Would appear, that one factor, in the attainment of the comparatively high propulsive efiiciency of this type of pr opeller for aircraft use is probably found in the fact that the density and force of 2 the air in the circumferential portion of the Slipstream around and in back of the enlarged ends of the propeller blades, is considerably increased.

It will benoted that the blades are formed, in cross-section, with sides tapering or beveled from 30 the longitudnal center line of the blades toward the leading and trailing edges; that is,othe crosssectional thickness of the blades decreases from the maximum on the longitudinal center-line of the blades to the minimum at the leading and 35 trailing edges.

The blade in the cross-section of its elements may be gradually varied for structural purposes, that is, the blade cross-section may be gradually decreased longitudinally in cross-sectional area 40 from the boss or hub [U portion toward the tip.

Likewise, it is to be noted that the pitch of the blades is gradually or progressively increased from zero at the longitudinal center line of the hub !t toward the tips of the blades to obt ain the maximum propulsive efiiciency.

While I have preferably indicated the revolution of the blades in a direction wherein the extension ll is on the leading edge, I do not wish to be understood as limiting myself to such direction of rotation, the blades may be arranged to be rotated with their extensions l 2 on the leading edges and the extensions l I located on the shorter radii on the trailing edges.

The extensions I! and |2 are preferably in the form of lobes or rounded extensions, however, I do not wish to be understood as limiting myself to rounded extensions, I prefer to use the word "lobe" synonomously with "extension" or an ex- 5 tended portion or area.

From the above description and attached drawings it will be readily apparent that I have provided a propeller which is characterized by the following novel features:

1. The propeller may be said to be a 'unit or a single member having a pair of oppositely disposed blades or blade portions formed integrally With a hub portion.

2. The longitudinal center-line of the drive shaft is the longitudinal axis of the hub portion or hub, and the blades are designed to evolve 1 ter of evolvement is disposed transversely to 'the 'longitudinal axis of the hub.

6. The leading edge of each blade is continuous with the trailing edge of the other blade.

7. Each blade has a pair of oppositely disposed relatively offset lobes, one on each edge thereof.

8. The blade portions, including the lobes thereof, are so formed that their cross-sectional thickness decreases from the maximum on the longitudinal center-line of the blades to the minimum at the leading and trailing edges.

9. Exclusive of the enlargements or lobes, the blades are uniform in width.

This application is a continuation in part of applicant's former application Serial No. 584374, filediJanuary 2, 1933, now abandoned.

' I claim:

1. A propeller blade having a pair of integral extensions substantially at the tip portion thereof, said extensions being oset relatively to each other and substantially of equal face area and being disposed one on the leading edge and the other on the trailing edge of the blade.

2. A propeller comprising a plurality of blades, each of said blades having an enlarged tip area consisting of a pair of integral extensions, one of said extensions being disposed on the leading edge of the blade, and the other of said extensions being disposed on the trailing edge of said blade, said extensions being substantially of equal face area and disposed at different radii from the center of revolution of said blades.

3. A propeller comprising a plurality of blades, each of said blades having an enlarged tip area consisting of a pair of integral extensions, one of said extensions being disposed on the leading edge of the blade, and the other of said extensions being disposed on the trailing edge of said blade, said extensions being substantially of equal face area and disposed at different radii from the center of revolution of-said blades, the extension on the leading edge of the blades being on a shorter radius from the center of revolution of the propeller than the extension of the trailing edge of the blades. V V

4. A propeller comprising a plurality of oppositely disposed blade portions, each of said blade portionshaving an enlarged face area substantially at its tip section, said section including a oppositely disposed blades connected with said pair of oppositely disposed integral extensions, one of said extensions being formed on the leading edge of each blade portion and the other of said extensions being formed on the trailing edge of each blade portion, the' extension on the leading 5 edge of each blade portion being disposed ona shorter radius from the center of revolution of the propeller than the extension on the trailing edge, and all of said blade portions being formed with a pitch which increases from zero at the center of revolution of the propeller toward the tips of the blade portions. V 5. A propeller blade having a pair of oppositely disposed lobes substantially at its tip portion, said lobes being offset relatively to each other, one on the leading edge and the other on the trailing' edge of said blade and being of equal face area.

6. A propeller blade as embodied in claim 5, and including said lobes formed integrally with said blade.

'7. A propeller blade having a pair of oppositely disposed lobes substantially at its tip portion, said lobes being of equal face area and offset relatively to each other', one of said lobes being on the leading edge of the blade and the other on the trailing edge,-. said lobe on the leading edge being disposed on a shorter radius from the center of revolution of said blade than said lobe on the trailing edge, the width of said blade being substantially uniform exclusive of' said lobes.

8. A propeller as embodied in claim '7, wherein said blade is formed with a pitch gradually increasing from zero substantially at the center line of its axis of rotation toward its maximum pitch at its tip portion.

9. A propeller as embodied in claim 7, wherein said blade is formed with a pitch gradually increasing from zero substantially at the center line of its axis of rotation toward its maximum pitch V A at its tip portion, and including said blade ofa 40 cross-section which decreases in area from its hub portion toward its tip,

10. A propeller comprising a, plurality of blades, each blade having a, pair of oppositely disposed lobes formed integrally with the blade substan- 4 tially at its tip portion, said lobes being offset relatively one to the other, one on the leading edge and the other on the trailing edge, the lobe on the leading edge being disposed on a shorter radius from the center of revolution of the propeller than the lobe on the trailing edge, each of said blades being formed of a cross-section which decreases in area from its hub portion toward its tip, the pitch of each blade increasing from zero substantially at the center of the axis of rotation to the maximum pitch at the tip of the blade, and the length of each of said blades being substantially greater than the width thereof at its tip portions.

11. A propeller as embodied in claim 10, and including said blades so formed that their widths are substantially uniform from the hub portions to the tips thereof, exclusive of the lobe extensions.

12. A propeller comprising a hub, a pair of hub, said blades having a pitch evolving from zero at their center of evolvement on a theoretical line passing through the center line of the longitudinal axis-of the hub, the sides of 7 said blades at their center of evolvement being disposed transversely to the longitudinal axis of the hub, a pair of oppositely disposed relatively ofset lobes formed integrally with each blade, one at the tip end of the blade and the 'other one being disposed Closer to the center of revolution of the propeller, said blades being uniform in width exclusive of said lobes, and the thickness of said blades decreasing in crosssectional area from the longitudinal center line of the blades toward the leading and trailing edges.

13. A propeller comprising a hub, a pair of oppositely disposed blades connected with said hub, said blades being formed with a pitch which increases from zero on a line which intersects the longitudinal axis of the hub to the maximum at the tips of said blades, each of said blades having a pair of oppositely disposed relatively offset lobes ormed integrally with the blade, said blades being uniform in width exclusive of said lobes, and the thickness of said blades decreasing in cross-sectional area from the longitudinal center-line of the blades toward the leading and trailing edges thereof.

14. A propeller having a hub and a pair of oppositely disposed blades formed integrally with said hub, said blades being substantially of uniform face Width from tip to tip, and of a longitudinal section which decreases longitudinally of the blades from a maximum thickness at the hub center to a minimum thickness at the blade tips, said blades also decreasng in transverse cross-section from the longitudinal center line of the blades to the edges thereof, the face of the blades at their theoretical center of evolvement at the hub center being disposed transversely to the longitudinal axis of the hub and the pitch of said blades evolving from zero from said center of evolvement, said blades including a pair of oppositely disposed lobes forrned integrally with each blade, said lobes on each blade being ofiset one to the other, one being at the tip end of the blade and the other being disposed closer to the center of the propeller, the cross sections of said lobes conforming to the cross sections and pitch of theblade portions.

15. A propeller having a hu-b and a pair of oppositely disposed blades formed integrally with said hub, said blades being substantially of uniform face width from tip to tip, and of a longitudinal section which decreases longitudinally of the blades from a maximum thickness at the hub center to a minimum thickness at the blade tips, said blades also decreasing in transverse cross-section from the longitudinal center line of the blades to the edges thereof, the face of the blades at their theoretical center of evolvement at the hub center being disposed transversely to the longitudinal axis of the hub and the pitch of said blades evolving from zero from said center of evolvement, said blades including a pair of oppositely disposed relatively oset lobes formed integrally with each blade, one being at the tip end of the blade and the other being disposed Closer to the center of the propeller, the cross sections of said lobes conforming to the cross'sections and the pitch of the blade portions, and the leading and trailing edges of both of said blades being continuous from blade to blade.

JOHN WEICHWALD. 

